# What is the SpotGamma Gamma Model?

The Gamma Model reflects the rate of change for Gamma per each of the six indices and ETFs. The x-axis reflects the underlying asset price and the y-axis reflects the notional value of Gamma for the selected Index or ETF. You can also click on the last two days to see how the Gamma is changing by clicking the button in the upper right.

On the chart, the current value is represented by teal and the next expiration value in gray. You want to see how Gamma will shift due around different events such as options expiration. Calls drive positive gamma positions while puts drive negative gamma positions. In areas where the lines have the highest slope, and are the most vertical, the rate of change for Gamma is very high, and we expect to see the largest amount of volatility or price movement. Conversely, for the areas with flatter slopes, we expect to see less volatility.

The Gamma model helps you see how Gamma is reflected relative to different prices. Also, it’s helpful to pair this chart with the above histogram charts displaying absolute gamma.

SpotGamma Subscribers can access this chart for the SPX, SPY, NDX, QQQ, RUT and IWM.